| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv prt] a [adj] period | 74 |
|
| 2 | over a [adj] period | 70 |
|
| 3 | over a [adj] period | 70 |
|
| 4 | [adv] a [adj] period | 58 |
|
| 5 | [adv] a long period | 41 |
|
| 6 | only a [adj] period | 25 |
|
| 7 | only a [adj] period | 25 |
|
| 8 | [adv] a short period | 22 |
|
| 9 | quite a [adj] period | 11 |
|
| 10 | quite a [adj] period | 11 |
|
| 11 | [adv] a limited period | 5 |
|
